Portable horizontal warm air furnace



Aug. 14,

Filed Dec.

PORTABLE HORIZONTAL WARM AIR FURNACE C. S. BESSER 2 SheetsSheet 1 'CHARLES S. BEssER,

INVENTOR.

ATTORNEYS Aug. 14, 1956 c. s. BE SSER 2,758,590

PORTABLE HORIZONTAL WARM AIR FURNACE Filed Dec. 17, 1952 2 Sheets-Sheet 2 CHARLES S. BESsER, INVENTOR.

ATTORNEYS United States Patent PORTABLE HORIZONTAL WARM AIR FURNACE Charles S. Besser, Charlotte, N. C., assignor to Besser Metal Products Corporation, Charlotte, N. C., a corporation of North Carolina Application December 17, 1952, Serial No. 326,530

6 Claims. (Cl. 126-110) This invention relates to warm air furnaces and it is the primary object of this invention to provide a warm air furnace of a type which uses oil or gas for fuel and which may be readily moved from one place to another and has means for burning its own products of combustion to such an extent that it is not necessary to connect the stack thereof to a chimney or to other means communicating with the exterior of the house in which the furnace is used.

It is another object of this invention to provide a furnace comprising a wheeled casing, having a blower at one end thereof, and an elongated housing, having a combustion chamber and a heating chamber therein, past which the cool air in the room to be heated is forced by the blower and is then discharged through an opening located at or adjacent the other end of the casing. The heating chamber communicates with the combustion chamber and has means connecting the same with a stack which extends upwardly through the casing and is connected to a medial portion of a transverse pipe to opposite ends of which medial portions of angularly disposed upwardly converging draft pipes are connected, the lower ends of the angularly disposed draft pipes being permanently open and thereby causing the cool air to pass upwardly therethrough so as to create a draft and draw the warm air upwardly through the stack disposed therebetween and the open upper ends of the angularly. disposed draft pipes and thence outwardly into the room.

Also, one of the angularly disposed draft pipes has the upper portion of a relatively small pipe disposed therein which is open at its upper end, the lower end of which is connected to an auxiliary combustion chamber projecting upwardly from the primary combustion chamber of the furnace. This auxiliary or secondary combustion chamber is directly heated by the flame in the combustion chamber and, thus, the products or gases of combustion which are caused by the fuel being burned in the primary combustion chamber, move upwardly through the auxiliary or secondary combustion chamber and, in so doing, any burnable portions are further burned or consumed by the heat of the auxiliary or secondary combustion chamber.

Thus, as the remaining products of combustion continue upwardly through the relatively smaller pipe, which extends from the secondary combustion chamber through one of the angularly disposed pipes thereabove, any burnable portions of the products of combustion are consumed to a degree where they will have no harmful effect and only a relatively small amount of contaminated gases will escape through the upper end of the relatively small pipe which extends from the secondary combustion chamber through one of the angularly disposed pipes. Accordingly, it is unnecessary to connect the upper end of the pipe which carries off the fumes of the minute particles of combustion to a chimney or other communication with the exterior of the house in which the furnace is disposed.

This apparatus is especially useful for temporary heatice ing of a building, such as one under construction, after the outside walls have been erected. It is also useful for heating'large auditoria, which ordinarily require no heating plant.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings in which- Figure l is a side elevation of the improved portable furnace; v

Figure 2 is a topplan view of the improved furnace;

Figure 3 is a fragmentary elevation along the line 3-3 in Figure l with the horizontal louvers shown in Figures 4, 5 and 7 omitted for sake of clearness;

Figure 4 is a fragmentary isometric view showing the louver structure and looking in the direction of the arrow 4 in Figure 3;

Figure 5 is a longitudinal vertical sectional view through the furnace showing a substantial portion of the blower in elevation and being taken substantially along the line 5-5 in Figure 2;

Figure 6 is a transverse vertical sectional view, mostly in elevation, taken substantially along the line 6-6 in Figure 5;

Figure 7 is a fragmentary vertical sectional view taken substantially along the line 7-7 in Figure 5.

Referring more specifically to the drawings, the numeral 10 broadly designates the casing of the improved furnace which comprises a top wall 11, a bottom wall 12 and side walls 13 and 14. A transverse frame member 20, which is preferably formed from sheet metal and is substantially U-shaped in cross-section and is closed at opposite ends, is suitably secured to the lower surface of the bottom wall 12 (Figures 5 and 6) and has an axle 21 mounted therein, on opposite ends of which ground wheels 22 and 23 are rotatably mounted for supporting the front portion of the casing 10. The rear end of the bottom wall 12 has the front ends of a pair of legs or handle members 24 suitably secured to the lower surface thereof, as by spot welding. The legs 24 extend rearwardly beyond the rear edge of the bottom wall 12 and then curve upwardly and then downwardly in a semi-circular manner and the lower ends thereof terminate in spaced relation to the level of the bottom 12 for supporting the rear end of the casing 10.

Reinforcing angle bars 27 and 28 (Figures 5 and 7) are suitably secured to the lower surface of the bottom wall 12 and extend forwardly from the rear edge of the bottom wall 12 and abut against the rear surface of the transverse frame member 20. Additional reinforcing angle bars 31 and 32 are also suitably secured to the lower surface of the front portion of the bottom wall 12 and extend from adjacent the front edge of the bottom wall 12 and abut against the front surface of the transverse frame member 20.

The rear end of the elongated tubular casing 10 is open, thus providing an air intake opening 33. Spanning the distance between the walls 11, 12, 13 and 14 adjacent the air intake opening 33 is an air filter or screen 34. The front or left-hand end of the casing 10 in Figure 5 is partially closed by a front wall 35 which has a flanged air discharge opening 36 therein, the flanges of which are circumscribed by and support a louver assembly broadly designated at 37. The louver assembly 37 includes a plurality of horizontally disposed louvers 40 which are disposed within a rectangular housing 41, said horizontally disposed louvers 40 preferably extending at an angle in cross-section and preferably being adjustable as to angularity about their respective axes. The rectangular frame 41 of the louver assembly 37 also has a plurality of vertically disposed louvers 42 therein which are spaced transversely from each other and extend from 3 the uppermost wall to the lowermost wall of the frame 41. The vertically disposed louvers 42 are also preferably adjustable about their respective axes and are disposed forwardly of the louvers 40.

The casing 10 of the furnace and the contents thereof are similar to those disclosed in my co-pending application entitled Horizontal Warm Air Furnace, Serial Number 326,529, filed December 17, 1952, of which the present application is a continuation in part.

Suitably secured to and spanning the distance between the top and bottom walls 11 and 12 and the side walls 13 and 14 is a funnel-shaped partition 50 (Figure which defines a rear blower chamber or compartment 51 and a front air distributing chamber or compartment 52. A blower housing 53 is disposed in the chamber or compartment 51 and has a blower fan 54 therein, and the funnel-shaped partition 50 is provided with an opening therein to which the open end of the blower fan housing 53 of the blower 54 is communicatively connected.

The rotary fan 54 is fixed on a shaft 56 journaled in the housing 53 and at least one side of the housing 53 has an air ingress opening 57 therein, The fan 54 may be driven in any desired manner and, in this instance, one end of the shaft 56 has a pulley 60 fixed thereon which is driven by a belt 61 also mounted on a pulley 62, which is fixed on the shaft 63 of an electric motor 65 suitably secured to the rear surface of the blower housing 53. The electric motor 65 is preferably thermostatically controlled and has an electrical cable 66 extending therefrom which passes through the wall 13 of the casing and is connected to a combination junction box and master switch 67 from whence electrical cables 70, 71, 72 and 73 extend. Cable 70 extends to a suitable plug 74 adapted to be connected to a suitable source of electrical energy, not shown.

The end of cable 71 remote from the junction box 67 is connected to a conventional thermostatic stack switch 75 which has a thermal element 76 extending therefrom (Figure 5) into a vertical stack to be later described. The cable 72 extends to a blower 77 of a gun-type, or blow-type, oil or gas burner 80 of conventional construction.

The cable 73 extends from the junction box 67 to a fan and limit switch 81 suitably supported on the side wall 13 of the casing 10 and which has a thermal element 82 (Figure 6) extending therefrom which penetrates the wall 13 of the casing 10 and terminates within the air distributing chamber 52. A suitable manually controlled thermostat or thermostatic switch 83 is also carried by the side wall 13 of the casing 10 and has a cable 84 extending therefrom to the thermostatic stack switch 75. p

The electrical connections for the electric motor 65 of the blower 53 and the various other electrical parts of the furnace are well known and constitute a conventional furnace control system of the type distributed by Minneapolis-Honeywell Regulator Co., Minneapolis, Minnesota, and therefore a further detailed description of the electrical connections for operating the blower motor 65 and the blower 77 of the burner 80 is deemed unnecessary. It might be stated, however, that the thermostat 83 controls the blower 77 of the burner 80, causing the blower 77 to start at a given minimum temperature, and upon the thermal element 82 of the fan and limit switch 81 being heated to a predetermined temperature, the circuit is completed to the motor 65 of the blower 53. The stack switch 75 merely functions to stop the blower 77 after it has been running a predetermined period in the event that the fuel is not ignited at the nozzle of the burner 80 at the proper time to heat the air moved by the blower 77 through the stack, to be later described, in which the thermal element 76 is disposed.

The blower housing 153 is supported on suitable angle brackets or standards 90 suitably secured to the bottom wall 12 of the casing 10. An elongated housing broadly designated at 91 is disposed within the air distributing chamber 52 and comprises a cylindrical wall which extends longitudinally of the casing 10 but which may be rectangular in crosssection, if desired. The housing 91 is spaced from the top wall 11, the bottom wall 12, and side walls 13 and 14. The front end of the housing 91 is closed by a fiat plate or wall member 93 and the rear end thereof is closed by a conically formed plate or end wall member 94.

The front portion of the interior of the cylindrical wall 92 is clothed with a refractory cylindrical wall 95 and the inner surface of the front wall 93 also has an inner wall 96 of refractory material disposed thereagainst and forming the end of a tire box or combustion chamber generally designated at 97.

The rear end of the combustion chamber 97 is open and the cylindrical wall 95 of the refractory material terminates substantially midway of the cylindrical wall 92 of the housing 91, and thus defines the front edge of a heating chamber generally designated at 100 in the rear portion of the housing 91. The heating chamber 100 is partially closed by staggered segmental bafiie plates 101, 102 and, in this instance, the baffie plate 101 cugages the inner surface of the right-hand side of the wall 92 (Figure 7) and extends inwardly and terminates in spaced relation to the opposite or the left-hand inner surface of the cylindrical wall 92. On the other hand, the baflie plate 102 extends from the inner left-hand surface of the cylindrical wall 92 and terminates in substantially spaced relation to the right-hand inner surface of cylindrical wall 92.

It will be noted that the free edges of the segmental bafile plates 101, 102, which are spaced from the cylindrical Wall 92, are formed at angles relative to each other whereby the lowermost corners of the free edges of the bafile plates 101, 102 are disposed in closer laterally spaced relationship than the uppermost corners of the free edges thereof. This arrangement of the free edges of the baffle plates 101, 102 is desirable due to the tendency of the heat generated by the burner to rise, and it is therefore desirable to create greater resistance to movement of the heated air adjacent the upper inner surface of the cylindrical Wall 92 than at the lower inner surface thereof. Each of the baflle plates 101, 102 has its periphery extending for more than 180 degrees, thus producing an overlap of their straight edges.

It will be noted that the burner 80 extends through the top wall 11 of the casing 10 and penetrates the upper portions of the cylindrical wall 92 and the cylindrical wall of the casing 10 and the combustion chamber 97, respectively, so that the nozzle end of the burner 30 is disposed within the combustion chamber 97. Thus, the flame from the nozzle of the burner 80 is projected into the combustion chamber defined by the refractory walls 95 and 96. Accordingly, some of the heat generated by the flame in the fire box or combustion chamber 97 is transmitted through the walls 95, 96, 92 and 93 to the warm air distributing chamber 52.

However, most of the heat is forced rearwardly within the housing 91, due to the blower 77 associated with the burner 80 and caused to travel in the direction of the arrows in Figure 5 into the heating chamber and past the segmental baffie plates 101, 102. A horseshoe-shaped hollow radiator 104, being in the form of a rectangular tube in longitudinal cross-section, surmounts that portion of the housing 91 defining the heating chamber 100. The radiator 104 is mounted on the housing 91 and is held in spaced relation to the housing 91 and the inside of the walls 11, 13 and 14 of the casing 10 by at icast one radiator support 105 at the front end of the radiator 104 and at least three heat-exchange pipes 112 at the rear end thereof. The radiator support 105 is connected to the top wall of the housing 91 and the bottom wall of the radiator 104 by any suitable means, and the heat-exta change pipes 112 communicatively connect the interior of the heating chamber 100 with the interior of the radiator 104 at points on the top and side walls of the housing 91 between the baflie plate 102 and the conical rear wall 94 of the housing 91.

Although the radiator 104 may entirely encircle the heating chamber 100, it is preferable that the lower portion thereof be cut away whereby the radiator extends through an arc of substantially more than 180 degrees or approximately 270 degrees. The radiator 104 may be of welded construction and the remote ends thereof are closed as at 106 and 106a (Figures 5, 6 and 7).

Suitable legs 110, 111 support the respective front and rear ends of the housing 91, having the chambers 97, 100 therein, in spaced relation from the bottom wall 12 of the casing 10. The uppermost of the heat-exchange pipes 112 is preferably of smaller inside diameter than that of the other heat exchange pipes 112 so as to prevent the heat from escaping without first filling the radiator.

The upper rear portion of the outer walls of the curved tubular radiator 104 has the lower end of a relatively large stack or pipe 114 connected thereto and communicating with the interior of the radiator 104. The vertically disposed stack 114 is preferably disposed in substantially vertical alinemcnt with the uppermost heat exchange pipe 112, and extends upwardly from the radiator 104 through the top wall 11 of the casing 10, in contact therewith, and the upper end of the stack 114 terminates in communicative connection with a medial portion of a relatively short transverse pipe 115 which is spaced substantially above the top wall 11 of the casing 10. The thermal element 76 extending from the stack switch 75 terminates within the pipe or stack 114 and the stack switch 75 is suitably supported on the exterior of said stack 114. The stack 114 and the parts connected to the upper end thereof, to be presently described, represent the most important feature of the present invention.

The pipe 115 extends transversely of the pipe 114 and opposite ends thereof are communicatively connected to the medial portions of first and second upwardly converging draft induction pipes 116 and 117, respectively, so as to form a generally A-shaped pipe assembly. These draft induction pipes 116 and 117 are also relatively short, the lower ends thereof being spaced substantially above the top wall 11 of the casing 10 and the upper ends thereof terminating in close proximity or in engagement with each other. All three of the pipes 115, 116 and 117 are preferably of substantially the same internal diameter as the stack 114. The pipe 116 has the upper portion of an angularly disposed combustion pipe 120, of substantially smaller outside diameter than is the internal diameter of the pipe 116, suitably secured to that inner wall thereof which is remote from the portion of the wall of the pipe 116 to which the transverse pipe 115 is connected. The upper end of the combustion pipe 120 preferably terminates substantially flush with the upper end of the pipe 116.

However, the lower portion of the combustion pipe 120 extends downwardly substantially beyond the lower end of pipe 116 and penetrates a closure plate 121 thrust through the upper end of a vertically disposed tubular member 112 which forms a secondary or auxiliary combustion chamber 123 therein, the lower end of the combustion pipe 120 terminating adjacent the upper end of the secondary or auxiliary combustion chamber 123.

The tubular member 112 extends downwardly through the top wall 11 of the casing 10 and snugly penetrates the uppermost portions of the cylindrical walls 92 and 95 to thus establish communication between the rear portion of the primary combustion chamber 97 and the secondary combustion chamber 123.

The closure member 121 for the upper end of the secondary combustion chamber 123 preferably has a peep opening 125 therein (Figure which is normally closed d by a pivoted lid 126 (Figures 2 and 5) pivotally mounted at 127, on the closure plate 121.

It will be observed in Figures 1, 2 and 5 that the blower 77 carries a fuel pump 68 which is driven in the usual manner in unison with the blower 77. A fuel intake pipe 69 and a return pipe 69a are connected to the fuel pump 68 and the end of the fuel intake pipe 69 remote from the fuel pump 68 is connected to a fuel filter 79 supported upon the top wall 11 of the casing 10. One end of a pipe 81 is connected to the other side of the fuel filter 79 and corresponding ends of the pipes 69a and 81 are connected to a tank or reservoir 85 which is suitably secured to the rear end of the casing 10 above the top wall 11 thereof by suitable plates 86 secured to the tank 85 and the side walls 13 and 14 of the casing 10. The tank 85 is adapted to contain a supply of liquid fuel or gas, indicated at F, (Figure 5) which may be introduced into the tank 85 by means of the filler pipe 87 which is provided with a removable cap 88.

Thus, when the blower 77 is running, the fuel pump 68 causes the fuel F to circulate between the same and the tank 85.

In operation, the blower 77 causes the air heated by the flame from the nozzle 80 in the combustion chamber 97 to move rearwardly within the housing 91 toward the blower 53. As the heated air moves toward the rear wall 94 of the heating chamber 100, the baflie plates 101, 102 offer resistance to the movement of the heated air with the result that a substantial proportion of the heat is transmitted to the cylindrical wall 92 defining the combustion chamber 97 and the heating chamber 100. Thus, the heated air is cooled somewhat due to radiation through the wall 92 of the housing 91 and then passes through the pipes 112 into the curved tubular radiator 104.

The heated air is further cooled as the heat is transmitted through the walls of the radiator 104 to heat the air in the air distributing chamber 52, so the air is cooled considerably as it subsequently passes upwardly through the stack 114. The upward surge of the air in the stack 114, which air has cooled considerably, but is still warmer than the atmosphere surrounding the stack 114, is further induced by the upwardly converging draft pipes, 116, 117 which cause the air to circulate around the area adjacent the furnace.

The stack 114 primarily serves to induce or permit the air heated in the combustion chamber 97 to flow through the heating chamber and the radiator 104 rather than passing directly from the combustion chamber 97, 123 to be discharged through the pipe 120. It is this air, heated in the combustion chamber 97 and passing from there to the heating chamber 100 and the radiator 104, that is utilized to heat the relatively cold atmosphere brought into the air distribution chamber 52 by the blower 53. It is thus seen that the heating chamber 97 and the radiator 104 serve as heat exchangers, whereby the air heated by the burner 80 heats the walls of the heating chamber 100 and the radiator 104 which, in turn, serve to radiate the heat thus obtained to the outside air forced through the air distribution chamber 52 by the blower 53. The air thus heated is discharged by the blower 53 through the air discharge opening 36 to thus circulate through, and warm the room or area wherein the furnace is disposed.

The direction and degree of circulation or" the warm air throughout the room or area is adjustable by means of the louvers 40, 42.

A suitably inverted U-shaped hood 131 is preferably positioned above the open upper ends of the pipes 116, 117, and has its medial portion spaced substantially above said pipes. The legs of the U-shaped hood 131, at opposite sides thereof, are suitably secured, as by welding, to opposite sides of the horizontal or transverse pipes 115. The hood 131 is provided to prevent the heated air from rising directly upwardly from the pipes 7 116, 117, 120 and thus scorching the ceiling of the room in which the furnace is disposed.

Now, ordinarily, the fuel is not entirely consumed by the flame from the nozzle of the burner 89 with the result that, heretofore, a considerale amount of the prodnets of combustion would be carried through the heating chamber 97 and would be discharged through the stack. However, the secondary or auxiliary combustion chamber 123 is heated only slightly less than the refractory walls 95 and 96 of the primary combustion chamber 9'? and, since the products of combustion tend to rise through the auxiliary combustion chamber 123 and the combustion pipe 120, the products of combustion and the gases created thereby are further consumed as they enter the secondary or auxiliary combustion chamber 123 and are even consumed more efficiently as they pass upwardly through the combustion pipe 120 which is also heated to a substantially higher temperature than the wall 94 of the heating chamber 100, for example.

Thus, all of the fuel and the unburned gases created thereby are cfiiciently consumed before the gases have approached the upper end of the combustion pipe 120 and the air is merely heated and relatively clean and free from smoke and unburned gases at the upper end of the combustion pipe 120. Thus, the air which passes from the upper end of the combustion pipes 120 and the pipes 116 and 117 is practically devoid of fumes or unburned gases of combustion, thereby obviating the necessity of connecting the stack to a chimney.

It is evident that the burning of the gases and unburned products of combustion in the secondary combustion chamber 123 and the combustion pipe 120 produces more heat from a given amount of fuel, thereby effecting substantially greater economy in the operation of the furnace than has heretofore been possible with furnaces heretofore in use.

The arrangement of the combustion chamber 97, the heating chamber 100 and the radiator 104 is substantially the same as that of my said co-pending application so that the upper surface of the hood 131 may readily clear the ceiling of any room in which the furnace may be used. As the air around the housing 91 is heated, the blower 53 is running and thus draws in air through the intake opening 33, through the screen 34, and forces the same into and through the air distribution chamber 52 and thus outwardly through the air discharge openings 36 and then between the louvres 40 and 42. Since the radiator 104 is spaced from the portion of the wall 92 defining the heating chamber 100 and is also spaced inwardly from the walls 11, 13 and 14 of the casing 10, it is thus claimed that the air circulated by the blower 53 moves past the outer surfaces of the. housing 91 and the outer and inner walls of. the radiator 104 thereby insuring efficient distribution of the air heated in. the combustion chambers 92, 123 and the heating chamber lfiil.

It is thus seen that I have provided a portable warm air circulating furnace in which the combustion chamber 97, the heating chamber 106' and the blower 53 are axially alined horizontally and wherein the radiator 104 surmounts the heating chamber 100 thereby providing a compact heating unit which will require a minimum of space. Further, the secondary combustion chamber 123 and the combustion pipe 120 provide a more efiicient means for burning the unburned products of cornbustion than has heretofore been provided in furnaces known to the applicant. The draft pipes 116, 117 induce a continuous movement of air around the combustion pipe 120 and past the opposite ends of the transverse pipe 115 to which the upper end of the stack 114 is connected, and thereby insures that the air will continuously circulate through these, past the stack 114 and the combustion pipe 120.

In the drawings and specification there has. been set forth a preferred embodiment of the invention and although specific terms are employed, they are used in a descriptive and generic sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. In a furnace having a primary horizontal combustion chamber and a fuel burner therein for generating heat, the combination of a housing forming a secondary combustion chamber and communicating at its lower end with said primary combustion chamber at a point adjacent said fuel burner, closure means for the upper end of said secondary combustion chamber, an open ended combustion pipe of relatively smaller size than the cross-sectional size of the secondary combustion chamber connected to said closure means and communicating with said secondary combustion chamber, said combustion pipe extending upwardly substantially above the combustion chamber, and means for inducing movement of air adjacent the open upper end of said combustion pipe whereby upon said heat being generated, the products of said heat being generated in said primary combustion chamber the secondary combustion chamber and combustion pipe will be heated to thereby cause the products of combustion to be further consumed as they enter and pass upwardly successively through the secondary combustion chamber and the combustion pipe, a heating chamber communicatively connected to said primary combustion chamber, a casing surrounding said heating and primary combustion chambers and having its walls spaced from the walls of the combustion chamber and the heating chamber, a radiator disposed between said casing and said heating chamber and being communicatively connected to the heating chamber, blower means for forcing air around and past the two combustion chambers and the radiator, an exhaust stack connected to the radiator and extending upwardly through the casing, and means communicatively connected to the upper ends of said exhaust stack and said combustion pipe for inducing an upward draft in said combustion pipe.

2. A furnace comprising an elongated horizontal wheeled casing having an air inlet opening and an air discharge opening at opposite ends thereof, an elongated housing closed at opposite ends thereof disposed within and in spaced relation to the inside surfaces of the walls of said casing, a primary combustion chamber disposed in one end of said housing, a fuel burner disposed in said primary combustion chamber for generating heat, a secondary combustion chamber communicating with the upper portion of the primary combustion chamber, closure means for the upper end of the secondary combustion chamber, an open ended combustion pipe extending upwardly from and communicating with said secondary combustion chamber and being of substantially less crosssectional area than that of the primary combustion chamher, a heating chamber disposed in communication with the primary combustion chamber and being a continuation thereof and being closed at its end remote from the combustion chamber, a radiator disposed in spaced relation between the outer walls of said housing and the inner walls of said casing, a plurality of piped connections between the heating chamber and the radiator, an exhaust stack connected to the radiator and extending through the casing to a point adjacent the upper end of the combustion pipe, means communicatively connected to the upper ends of said exhaust stack and said combustion pipe for inducing an upward draft in said combustion pipe, and blower means mounted in the end of the casing remote from the combustion chamber for directing blasts of air against and past the closed end of the heating chamber, radiator and combustion chamber and out of the casing through said air discharge opening.

3. A furnace comprising an elongated horizontal cas ing open at both of its ends, an elongated housing closed at opposite ends thereof disposed within and spaced from the walls of said casing, one end of said housing defining a primary combustion chamber, a fuel burner disposed in said primary combustion chamber, a secondary combustion chamber communicating with the upper portion of the primary combustion chamber, closure means for the upper end of the secondary combustion chamber, a combustion pipe extending upwardly from and communicating with said secondary combustion chamber and being of substantially less cross-sectional area than that of the primary combustion chamber, a heating chamber joined to the open end of the primary combustion chamber and being in open communication therewith, a radiator surrounding a portion of said housing, a plurality of pipes joining the radiator to the heating chamber, an exhaust stack communicating with the radiator and extending upwardly through the casing, means communicatively connected to the upper ends of said exhaust stack and said combustion pipe for inducing an upward draft in said combustion pipe, and blower means disposed in the end of the casing remote from the combustion chamber for directing air past the exterior surfaces of the heating chamber, the radiator and the combustion chambers.

4. Heating apparatus comprising an elongated casing open at both of its ends and having an elongated housing disposed in the casing and closed at both ends and extending longitudinally of the casing and spaced from the walls of the casing and providing a primary combustion chamber in one end thereof and a heating chamber in the other end thereof, a fuel burner communicatively connected with said primary combustion chamber, a radiator disposed between said housing and said casing and piped connections between the radiator and heating chamber, an exhaust stack communicatively connected to the radiator and extending upwardly through the casing, a secondary combustion chamber communicatively connected to the primary combustion chamber adjacent the upper medial portion thereof, a combustion pipe communicatively connected to the secondary combustion chamber and extending upwardly therefrom, the upper ends of said exhaust stack and said combustion pipe communicating with the atmosphere at adjacent points spaced from said casing, and blower means disposed in the end of the casing remote from the primary combustion chamber for forcing air around and past the heating chamber, the combustion chamber, the radiator and the secondary combustion chamber and out of the other end of the casing.

5. Heating apparatus comprising an elongated casing open at both of its ends and having an elongated housing disposed in the casing and closed at both ends and extending longitudinally of the casing and spaced from the walls of the casing and providing a primary combustion chamher in one end thereof and a heating chamber in the other end thereof, a fuel burner disposed in said primary combustion chamber, a radiator in said casing and communicatively connected to the heating chamber, an exhaust stack communicatively connected to the radiator and extending upwardly through the top wall of the casing, a secondary combustion chamber communicatively connected to the primary combustion chamber adjacent the upper medial portion thereof, blower means disposed in the end of the casing remote from the primary combustion chamber for forcing air around and past the heating chamber, the combustion chamber, the radiator and the secondary combustion chamber and out of the other end of the casing, a cross pipe connected to the open end of the exhaust stack, a pair of upwardly converging draft induction pipes open at both ends and communicatively connected intermediate their ends to the cross-pipe, and a combustion pipe communicatively connected to said secondary combustion chamber and extending upwardly therefrom through one of said draft induction pipes.

6. Heating apparatus comprising a casing, a housing disposed within the casing and extending longitudinally thereof, a fuel burner disposed within the housing, the housing being closed against communication with the interior of the casing, a radiator disposed within the casing and communicatively connected with the interior of the housing, an exhaust stack communicating with the interior of the radiator and extending upwardly through the top of the casing, an open ended combustion pipe communicatively connected to the housing at a point adjacent said fuel burner, said combustion pipe extending upwardly from said housing, and means communicatively connected to the upper ends of said exhaust stack and said combustion pipe for inducing an upward draft in said combustion pipe.

References Cited in the file of this patent UNITED STATES PATENTS 297,972 Day May 6, 1884 299,175 Sheets May 27, 1884 2,043,487 Norris June 9, 1936 2,172,399 Mueller Sept. 12, 1939 2,240,161 Mueller Apr. 29, 1941 2,259,187 Turnbull Oct. 4, 1941 2,302,859 Hare Nov. 24, 1942 2,383,431 Weyenberg Aug. 21, 1945 2,504,315 Feuerfile Apr. 18, 1950 2,573,651 Ruff Oct. 30, 1951 

